Fluid pressure system



April 1940. E. F. LCWEKE 2,196,930

FLUID PRESSURE SYSTEM Filed Dec. 3, 1937 2 Sheets-Sheet 1 I v INVENTOR. 'ermv F4 owls/r5 ATTORNEY.

Ap 9, 1940. E. LOWEKE FLUID PRESSURE SYSTEM Filed Dec. 3, .1937 2 SheetsSheet 2 5 INVENTOR. few/Al F L OWE/(E ATTORNEY.

Patented Apr. 9, 1940 UNITED STATES PATENT OFFICE Hydraulic Brake Company,

rnia

corporation of Caliio Detroit, Mich., a

Application December 3,1931, Serial No. 178,000 '1 Claims. (01. 60-545) This invention relates to fluid pressure systems. An object of the invention is to provide-a fluid pressure system for energizing a remote fluid pressure actuated motor. I

' Another object of the invention is a duplex fluid pressure producing device having a single actuator operative to successively actuate the fluid pressure producing devices.

Another object of the invention is to provide a fluid pressure system including a duplex fluid pressure producing device, operative successively, and opposed fluid pressure motors connected thereto having connected therebetween a shiftable element.

Other objects and-advantages of the invention will appear from the following description taken in connection with the drawings forming a part of this specification, and in which- 1 Fig. 1 is a top plan view of a motor vehicle 9 chassis partly broken away illustrating the invention as applied;

Fig. 2 is a vertical sectional view .0! the fluid pressure producing device;

Fig. 3 is a sectional viewsubstantially on line 3-3, Fig. 2;

Fig. 4 is a top plan view of the shifting mechanism and fluid pressure motors for actuating the shifting mechanism, the motors being shown in section; and

Fig. 5 is a top plan view of a two-speed axle,

) partly broken away, the shifting mechanism, and

the motors.

Referring to the drawings for more specific details of the invention, l0 represents a motor vehicle chassis frame supported on springs, not

shown, generally suspended from a frontaxle, al-,

so not shown, and a rear axle l2 having suitably mounted thereon for rotation wheels I 4- of con ventional type. The axle l2 has connected therein adifierential l6, and associated with the differential is a two-speed transmission I8 includlng a shiitable gear 20.

A casing 22 secured to the housing of the differential has mounted therein for oscillation a 'shaft 24 extending through and beyond the casing, and a sleeve 26 keyed on the shaft within the casing'carries a 'fork 28 embracingthe shiftable gear 28. The sleeve 28 alsocarries a lever 88 having adjacent its free end spaced recesses 32 for the reception of a spring-pressed plunger 34 mounted on the wall of the casing for yieldingly retaining the lever against movement, and suitably secured to the shaft outside of the casing 'is an operating lever 36.

A fluid pressure producing device, indicated generally at 38, is suitably mounted on the frame III of the vehicle chassis. This fluid pressure producing device includes a reservoir 40 provided with a filling opening 42 normally closed as by a plug 44 having openings 46 therethrough for 6 venting the reservoir to the atmosphere. The reservoir is open at its bottom as indicated at 48, and depending from the bottom are corresponding parallel cylinders 50 and 52 opening into the reservoir. The cylinders have heads 54 and 56 10 provided with discharge ports 58 and 68 controlled as by two-way valves 62 and 64 seated on the heads. A pair of corresponding. pistons 66 and 68 re- I ciprocable in the cylinders 50 and 52 each in- 15 clude a shell 10 open at one-of its ends and closed at'its other end. The closed end of the shell provides a head 12 having a port 14 providing a communication between the interior of the shell and that portion of the cylinder forward of the piston. A sealing cup I6 seated on the head has an axial opening 18, and the perimeter defining this opening overhangs the port 12, the object of which will hereinafter appear. A spring 80, interposed between the cup, 16 and the valve con- 25 trolling the discharge port, serves to retain the cup and the valve against displacement and also to return the piston to its retracted positionagainst a stop 82 secured to the partition between the cylinders.

A plunger 84 reciprocable in the shell 10 has one of its ends 86 reduced in cross-section so as to provide anannular shoulder 88 adapted to .seat on the stop 82 when the plunger is in retracted position. The other end 90 of the plunger is also reduced in cross-section so as to provide an annular shoulder 92, and sleeved on this end of the plunger between the annular shoulder 82 and the back of the head i2 of the shell is aspring 94 normally urging the plunger to itsretracted 40 position.

' The plunger also has a plurality of spaced passages 98 therethrough; providing communications between the reservoir and the port in the head of the shell, and a concentricextenslon 98 45 on its reduced end adapted to enter and close the port in the head of the shell and also to engage the overhanging perimeter of the cup defining the opening therein so as to eflectively seal the port. g The extension 98 has thereon a concentric pin I00 extending through the port in the head 12 and the opening in the sealing cup 16 with substantial clearance. The pin has a header greater diameter than the port, and the pin is slotted as indicated at I02. This pin serves to retain ing beam I86 also includes an arm II2 arranged centrally between the arms I 08 and H0, and on the free end of this arm H2 is a tooth H0.

A. shaft H6 mounted transversely of the reservoir above the shaft I02 and parallel thereto has suitably secured thereon within the reservoir a sleeve M8 supporting an actuator I20 having upon its free end a tooth I22 arranged for cooperation with a tooth I It on the arm H2, and suitably secured to the shaft H6 outside of the reservoir is an operating lever I28.

Fluid pressure delivery pipes or conduits I26 and I28 connect the discharge ports 58 and 60 of the cylinders 50 and 52 to fluid pressure actu ated motors I30 and I32 for'actuating the operating lever 36 of the transmission I8. The motors are suitably supported in a fixed position in oppositely disposed relation to one another.

Each of the motors I30 and I32includes a cylinder I38 having communicating chambers I36, I38 and I 80. The chambers I36and I20 are of substantially the same diameter, and the chamber I38 has a somewhat smaller diameter.

The cylinder has a port IE2 at the junction of the chambers I36 and I38, controlled as by a bleeder screw I40, and an intake port I66.

Opposed pistons I08 and I50 are mounted for reciprocation in the cylinders I36 and I38, and sealing cups I52 and I54 seated on the heads of the pistons are held against displacement by a spring I56 interposed between the cups. The piston I48 has in its back a recess for the reception of a thrust pin I58 suitably connected to the lever 36, and the piston I50 has on its back a flange I60 normally seated on the annular shoulder at the junction of the large and small chambers; "and in the back of the piston I50 is a recess receiving one end of a spring I62, the other end of which is seated in a recess in an adjustable screw I60 mounted for travel in a plug I66 thread ed in the open end of the chamber I60.

In a normal operation, upon movement of the operating lever I20, the tooth I22 thereon engages the tooth I I4 on the arm I I2 of the walking beam I06, and transmits force thereto. This results in rocking the walking beam I06 and the transmission of force through the arm I08 thereof to the plunger 88 of the piston 66, resulting in advancing the plunger 84 against the resistance of the spring 94. During the initial movement of the plunger. the extension 98 thereon enters and closes the port II in the head of the piston 66, and thereafter the plunger and piston move as a single unit. As the piston advances on its compression stroke, the fluid in the cylinder forward of the piston is displaced therefrom. past the twoway valve 62, through the discharge port 58 and the conduit I26, into the fluid pressure actuated motor- I30, causing energization of the motor. This results in movement of the lever 36 accompanied by rocking of the shaft 24, and this movement of the shaft 24 is transmitted therefrom through the fork 28 to the gear 20, resulting in shifting the transmission to the low speed posh tion.

' upon the walking beam I06 is returned to its normal position under the influence of the springs 96 urging the plungers 84 of the pistons 66 and 68 to their retracted positions.

Also, during this operation the quantity of fluid displaced from the cylinder and received by the motor I30 may be in excess of the quantity necessary to efiectively actuate the transmission. This would impose undue strain on the mechanism and also inhibit tripping of the actuator due to the locking of the tooth I22 on the actuator with the tooth I It on the arm I I2 of the walking beam I06. -Accordingly, to avoid this condition, the motor I30 is provided with a reciprocable piston I50 normally held on its seat by a spring I62 having sufficient tension to resist the pressure in the chamber I36 of the motor until adequate pressure has been attained to effectively shift the transmission, and thereafter to yield sufficiently to provide for a complete movement of the operating lever I28.

In shifting the transmission from the low speed position to the high speed position, the operating lever I26 is moved from its forward position backwardly. This movement of the operating lever I20 again engages the tooth I22 on the actuator with the tooth I I I on the walking beam I06, resulting in rocking the walking beam and the transmission of force therefrom through the arm H0 to the plunger 80 in the piston 60, causing actuation of the plunger.

During the initial movement of the plunger the extension 88 thereon enters and closes the port It, and thereafter the plunger and the piston 68 move as a single unit; and as the piston advances on its compression strokethe fluid in the cylinder 52 forward of the piston 68 is dis placed therefrom past the two-way valve 6% through the discharge port 60 and the fluid pressure delivery pipe I28 into the fluid pressure acrocking the shaft 24 keyed to the lever, and this movement of the shaft is transmitted through the fork. 28, keyed thereto, to the gear 20, resulting in movement of the gear and thereby shifting the transmission to the high speed position-thus completing the cycle.

Although this invention has been described in connection with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is:

1. A fluid pressure producing device comprising a pair of cylinders, apiston reciprocable in each cylinder, a walking beam having its oppositely disposed arms engaging the pistons, a centrally disposed arm on the walking beam, and an actuator having an overrunning tripping engagement with the free end of the centrally disposed arm.

This energization of the motor I32 rea pair of cylinders. a. piston reciprocable in each cylinder, a walking beam having its oppositely disposed arms engaging the pistons, an arm centrally disposed on the walking beam, a tooth on gage the tooth on the upwardly extendingarm.

4. A fluid pressure producing device comprising a pair of parallel cylinders, a piston reciprocable in each cylinder, a walking beam mounted between the pistons for selective actuation thereof, a centrally disposed upwardly extending arm on the walking beam having a tooth on its free end, and an actuator, having a tooth thereon adapted to engage the tooth on the centrally disposed arm in both forward and reverse movement and to trip after a predetermined movement in either direction.

5. A fluid pressure producing device comprising a reservoir, a pair of cylinders depending therefrom and communicating therewith, a piston reciprocable in each cylinder having means effective for by-passing fluid when not on its compression stroke, a walking beam mounted between the pistons having its oppositely disposed arms normally engaging the pistons, a centrally disposed upwardly extending arm on the walking beam, a tooth on the free end of the upwardly extended arm, an actuator rockably mounted in the reservoir above the walking beam, a tooth on the actuator cooperating with the tooth on the upwardly extended arm, and means for rocking the actuator.

6. A fluid pressure system comprising'a duplex fluid pressure producing device including a reservoir, a pair of cylinders depending therefrom and communicating therewith, a piston reciprocable in each of the cylinders having means eil'ective for by-passing fluid when not on its compression stroke, a walking beam mounted between the pistons having its oppositely disposed arms in engagement therewith, a centrally disposed upwardly extending arm on the walking beam. having a tooth on its free end, an actuator having a tooth adapted to engage and ride over the tooth on the centrally disposed arm, a fluid pressure actuated motor connected to each cylinder, and a shiftable element connected between the motors.

7. A fluid pressure system comprising a duplex fluid pressure producing device including a reservoir, a pair 01' cylinders depending therefrom and communicating therewith, a fluid pressure actuated motor connected to each of the cylinders,'a 2

the reservoir having its respective ends engaging 80 the pistons .iorv selective actuation thereof, a centrally disposed upwardly extending arm on the walking beam, and an actuator adapted to engage the centrally disposed arm in both forward and a predetermined movement in either direction so as to release the pressure in the system.

ERWIN F. LOWEKE.

reverse movement and to trip over the arm after 35 

